fix: bad audience in camunda cloud channel factory, clean parameters in camunda cloud channel factory

[dimastbk]

fix #510

I suggest allowing only the required options to be set, like in the Java SDK

ping @felicijus

[coveralls]

Pull Request Test Coverage Report for Build 11277692278

Details

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.005%) to 96.927%

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Totals
Change from base Build 11277676454:	0.005%
Covered Lines:	1104
Relevant Lines:	1139

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💛 - Coveralls

[felicijus]

If i remember correctly Spring Boot SDK for Zeebe sets these parameters by default too.
@dimastbk

[dimastbk]

Spring Boot SDK calculates audience, scope isn't required by Camunda Cloud and oauth url is static

[dimastbk]

I tested this changes with Camunda SaaS

[felicijus]

Can I check myself tomorrow, currently i only got my phone?

[felicijus]

1. audience should be static Camunda Docs
   audience="zeebe.camunda.io
2. scope should either be None (Optional parameter), because setting it to the cluster_id also works. Maybe relevant for enterprise user with custom scope configs...
3. leeway and expire_in i don't really know if there is need for customization. Would not hurt to keep I guess.

#510 Is an import error, where the old create_camunda_cloud_channel function was used. (The old function also needs a static audience)

Do we want to close this pull-request then and I will provide a fix for the scope issue ?